Various forms of strap fastener assemblages have been developed for preferred use with an automatic fastener driver. In one particular type of assemblage, such as disclosed in FIGS. 29 and 30 of U.S. Pat. No. 5,005,699, a plurality of collated screws are secured together with a pair of parallel connecting wires arranged with a predetermined spacing along the axes of the wires. Points of contact between the thread of each screw and the wires are joined by spot welding.
There are difficulties associated with the aforementioned screw package. For example, since the wires are secured directly to the threads by means of spot welded joints, the random screw thread surface yields a typical lack of uniformity in weld quality. For example, one screw may be rotated so that the weld electrode or wheel for the weld wire is on a valley between two threads, and thus the wire does not touch the screw and no weld is made. On a subsequent screw, the weld wheel may hit a peak of a thread, and sever the weld wire.
This leads to subsequent difficulty with power tool interface. In other words, some screws may not be attached to the weld wire at all. In subsequent screws, fragments of the wires may stay with or break free from the threads. Those wire segments that break free can inhibit consecutive screws from proper indexing forward in the tool. Also, the wire segments that remain attached to the threads create discontinuity and inhibit smooth interface of the threads with wood fiber in a secure fastening operation.
It is accordingly one object of the present invention to provide a screw package wherein a plurality of screws are held together in collated alignment with a frangible material that does not interface with the threads.
Another object is to provide for a collated screw package in which wires are spot welded in a manner guaranteeing consistent spot welds irrespective of thread specifications.